Method of making a tobacco product



r 3,298,378 Ice Patented Jan. 17, 1967 METHOD OF MAKING A TOBACCO PRODUCT Chester U. Stevens, Stockbridge, Mass., William P.

Schweitzer, Colts Neck, N.J., and William A. Selke,

Stockbridge, Mass., assignors to Kimberly-Clark Corporation, Neenah, Wis., a corporation of Delaware N Drawing. Filed Jan. 30, 1964, Ser. No. 341,443

1 Claim. (Cl. 131-140) This invention relates generally to tobacco and tobacco products, and has particular reference to a process for making a novel type of tobacco product having improved smoking qualities.

By the term smokable articles it is intended to refer to cigars, cigarettes, smoking tobacco, and similar products affording a means for enjoyment of the flavor and aroma of burning tobacco.

It is a general object of the invention to provide a process for making a tobacco product whose combustion characteristics have been so modified that less tars are generated during pyrolysis.

Another object is to provide a process for making a tobacco product of the character described, composed essentially or wholly of substances derived from natural tobacco.

Another object is to achieve these results without impairment or unfavorable modification of the general appearance, texture, aroma, and desirable smoking qualities of the product.

Another object is to produce a tobacco product, and smokable articles prepared from it, having the advantageous characteristics referred to, .by a procedure which is thoroughly practicable on a commercial scale and econornically feasible.

It is well known that the composition of natural tobacco leaf includes aromatic and resinous substances, alkaloids, sugars and salts of various kinds, and crude fibers. The aromatic and resinous substances provide desirable smell and taste during pyrolysis, but the burning of the fibers produces only the characteristic smoke of burning cellulose and contributes very little to the aroma. For this reason, and also because the products of their pyrolysis include tars which may be considered harmful, natural tobacco fibers are not essential ingredients of a tobacco product so far as their smoking qualities are concerned. As fibers, however, they are useful in the formation of a carrier for a sheet-like tobacco product from which smokable articles can be made. It is a general object of this invention to provide a method of manufacture and treatment which serve in effect, to eliminate the fibers contribution of tars to the smoke but to retain them entirely or at least in major proportion, as components of a fibrous carrier for the more desirable values of the tobacco leaf. This general objective is achieved by extracting soluble material from natural tobacco, treating the remaining fibers to modify their natural combustion characteristics, forming a porous sheet composed essentially of such combustion modified fibers, and

cipitate intimately incorporated in a firmly adherent manner within and between the fibers and fibrils. It may be brought about either prior to or after the conversion of the fibers into the form of an absorbent fibrous sheet. Addition of commercially available TiO pigments to the fibers, or at any other stage in the process of preparing a smoking article, does not produce a comparable effect on the smoking characteristics of tobacco.

It is to be understood that the term combustionmodified as used herein and in the appended claims is intended to refer to a modification of the natural combustion characteristics of the fibers whereby the relative proportions of the normal products of combustion are markedly changed by a reduction in the proportionate amount of tarry residue. Thus, whereas the pyrolysis of natural cellulose yieldscombustion products containing in the neighborhood of 50% of tarry condensate, the pyrolysis of the modified fibers of the present invention shows a large reduction of the tarry fraction.

An illustrative procedure conforming essentially to the objectives and features of the invention is depicted in the following flow chart:

NATURAL TOBACCO COMBUSTION-MODIFYING 'raaarrrsur roamrzos 0F sssoasaaw sneer TOBACCO PRODUCT The original tobacco may be in leaf or other form, preferably macerated or comminuted in preparation for the extraction. The extraction is facilitated by the use of hot water, and generally withdraws from 25% to 60% by weight of the starting material. The remaining fibers may be subjected at once to the special modifying treatment, or (as indicated in dotted lines) a further extraction with organic solvents may be resorted to, if desired, to recover selected values still retained by the fibers. Ethyl ether or other low ethers, acetone or other low boiling ketones, are examples of such solvents.

The modifying treatment can be optionally performed in any of several ways, and a number of soluble salts of titanium may be employed to achieve the desired objective, The mineral acid salts are particularly eifective, such as chloride, the sulfate, the nitrate, and others. All have the general formula TiOCl TiOSO etc. Other useful salts are titanium chloride acylates, and salts of similar type, the acylate group being a derivative of a carboxylic acid such as formic, acetic, or propionic acid. The treating solution is used to saturate the extracted tobacco fibers, and after time for thorough penetration into the fibers it is neutralized for an appropriate period with any convenient alkali such as sodium carbonate. Excess alkali and by-product salts are then washed away, leaving the fibers with a firmly attached and intimately incorporated fine dispersion of titania.

The application of the treating solution to the tobacco fibers can be made in various ways. For example, the

fibers can be immersed; or the solution can be sprayed onto the wet fibers before or after extraction; or the web can be formed first and the treating solution then applied by dipping or spraying. Any other suitable or conveniient saturating procedure may be employed.

Illustrative of the procedure are the following examples:

Example I A treating solution (TiOCl was prepared by slowly introducing 380 grams of titanium tetrachloride (TiCl into 620 grams of a mixture of cracked ice and water, with good agitation.

Bright leaf tobacco (100 grams) was extracted with hot water, and the dilute liquor was concentrated by evaporation and temporarily set aside. The remaining fibrous material was dried, then subjected to the combustionmodifying treatment. This involved immersion of the fibers in the treating solution and squeezing them free of excess liquid. After 15 minutes the moist tobacco fibers were rapidly mixed into 500 ml. of a 15% sodium carbonate solution and then washed thoroughly, leaving a deposit of finely dispersed titania precipitate.

By usual papermaking techniques the treated tobacco fibers were then formed into a sheet. This involved formation of an aqueous slurry containing the fibers (suitably beaten) and the transformation of the slurry into a self-sustaining absorbent web. The resultant sheet had a basis weight of 24- pounds per ream, which is within the desired range of 8 to 40 pounds per ream of 2000 square feet, roughly equivalent to the weight characteristics of natural tobacco leaf. An analysis of the sheet revealed the presence of about 13%, 'by weight, of titania.

The tobacco extract was then introduced into the sheet in substantially the same proportion as in natural tobacco, i.e., the ratio of tobacco solubles to fibers was approximately the same. The web was then cut into fine shreds and made into cigarettes. Its golden brown color was substantially that of natural flue-cured tobacco leaf, and its smoking flavor was excellent.

For comparison with conventional cigarettes in evaluating tar yields, two kinds of control cigarettes were produced. Type I was made in exactly the manner described, except that the combustion-modifying treatment was omitted. Type II was made with shredded tobacco obtained from package of currently-popular commercially available non-filtered cigarettes. These three groups of cigarettes were tested for tar product by the method described by J. A, Bradford in volume 28 of Industrial and Engineering Chemistry (pages 836839) in an article entitled Nature of Cigarette Smoke-Technic of Experimental Smoking. The results were as follows:

Cigarettes: Tar production per cigarette, milligrams Type I control 27 Type II control 36 Cigarettes per Example I 7 Example II The procedure of Example I was followed except that the fibers were not dried before being subjected to the combustion-modifying procedure. Instead, the wet fibrous material, immediately after the extraction, was sprayed with 15 grams of titanyl chloride solution and after 15 minutes the fiber was neutralized as described in Example I.

An analysis of the fibrous sheet, prior to the introduction of the tobacco extract, showed about 4% of titania.

Testing the resultant cigarettes in accordance with the test procedure described, it was found that tar production was 14 mg. per cigarette.

Example III The procedure of Example I was followed, except that the combustiou-mfldifying treatment was performed after the fibrous web had been formed. The web was sprayed with 15 grams of titanyl chloride solution, and after penetration, neutralization and washing, as previously described, the tobacco extract was applied to the treated sheet.

An analysis of the fibrous sheet, prior to the introduction of the tobacco extract, showed about 3% of titania.

Testing cigarettes made from this sheet, employing the test procedure described, it was found that tar production was 18 mg. per cigarette.

Example IV The procedure of Example II was followed, using 15 grams of titanyl sulfate solution instead of titanyl chloride. The concentration of the sulfate solution was substantially the same as that of the chloride solution, The

sheet was found to hold about 3% of titania precipitate,

and cigarettes made from the resulting sheet, tested as before, showed a yield of 17 mg. of tar per cigarette.

* Example V A treating solution of titanyl chloride-acetate was formed by slowly adding a concentrated lead acetate solution to a solution of TiOCl in amount equivalent to 4065% of the chloride present. The precipitated lead chloride was then filtered out.

The treating solution was applied to the extracted tobacco fibers in the manner described in Example II instead of titanyl chloride. The same amount and concentration of treating solution were used, and the procedure of Example II was followed in all other respects. There was about 3% titania in the fibrous sheet before introduction of the tobacco extract. Cigarettes made from the resulting sheet were tested as hereinbefore described, and were shown to produce 17 mg. of tar per cigarette.

Example VI The procedure of Example II was followed, except that only 9 grams of titanyl chloride solution was applied to the wet stock. Analysis of the fibrous sheet, before introduction of the tobacco extract, showed the presence of about 1.5% of titania precipitate. Following the previously described process, cigarettes were prepared and test-smoked, and about 22 mg. of tar per cigarette were found.

As the foregoing examples indicate, the tarry residue produced by the smoking of the cigarettes described is appreciably lower in quantity than that resulting from the smoking of cigarettes comprising tobacco untreated in accordance with this invention. This can be attributed directly to the described treatment which modifies the combustion characteristics of the tobacco fibers, as the following test procedures indicate.

Tobacco was extracted and portions of the remaining fibers were treated with dfferent amounts of titanyl chloride as previously described, to establish a firmly adherent deposit of finely dispersed titania precipitate within and between the fibers. The treated fibers were made into sheets by the usual papermaking procedures. The sheets were dried and then, without introduction of the extracted soluble tobacco matter, they were shredded, and the shreds were made into cigarettes. The cigarettes were test-smoked in the usual way except that air was drawn continuously through the burning cigarette, rather than in intermittent puffs, in order to collect the entire amount of tars produced. The amount of tar produced at each level of treatment is shown below:

Titania in sheet (per cent of dry Tar produced (mg. per gm. of dry Modifications of the basic procedure may be made without departing from the objective. For example, while it is entirely satisfactory to retain and modify the combustion characteristics of all the fibrous tobacco material left by the extraction process, it may be desirable under some circumstances to discard some of the fibers and replace them with others, such as wood pulp or asbestos or glass, or with inorganic solids. Wood pulp fibers are cellulosic, of course, and have some of the shortcomings of tobacco fibers with respect to products of pyrolysis, but they are useful to enhance the webforming interengagement of fibers when the carrier sheet is formed. Generally a retention and combustion modification of at least 50% of the natural tobacco fibers remaining after extraction of solubles attains the benefits of the invention to best advantage, but a lesser amount of treated fiber may be used (e.g., as little as 33%) and still bring about a significant reduction in the tar content of the smoke.

Other modifications are equally feasible, involving and scope of the invention as expressed in the appended claim.

What is claimed is:

A process for making a tobacco product for use in a smokable article which comprises extracting the soluble material from natural tobacco to leave a fibrous remainder, forming the said remaining fibers into a sheet by a paper making technique, impregnating the fibers thereof with a soluble titanyl salt selected from the group consisting of titanyl chlorides, sulphates, nitrates and acetates which is reacted with an alkaline neutralizing agent to occasion a titania impregnation thereof and finally incorporating the soluble extract into the sheet .in substantially the same proportion as that present in the natural tobacco, the titania impregnation modifying the natural combustion characteristics of the fibers so that the percentage of tarry condensate produced by combustion thereof is reduced.

References Cited by the Examiner UNITED STATES PATENTS 2,007,407 7/1935 Sadtler 13143 X 2,080,437 4/ 1937 Rafton 162--181 2,755,207 7/1956 Frankenburg l3115 3,106,211 10/1963 Reynolds et al. 13117 3,145,717 8/1964 Osborne et al 131-140 SAMUEL KOREN, Primary Examiner.

MELVIN D. REIN, Examiner. 

